Dark Wings
by sikeminatural
Summary: Sam is persuaded to go ‘dark side’ by Ruby but once he’s turned, there’s no turning back and Sam can’t control his dark side anymore. Dean is torn up with guilt brought on by a secret deal made with Castiel and he realises that he has to stop his brother.
1. Prologue

_**Prologue**_

Sam looked at his reflection in the mirror and wondered who he was. Was he still Sam Winchester, the human? Or was he Sam Winchester, the demon? He didn't think he'd ever really know. But the yellow eyes that stared back at him told him that he was evil, he had to unleash his evil. It was time to make Lilith pay for what she'd done. But how could Sam go back from this; he'd gone 'dark side' he'd never be the same again. There would be other hunters thirsting for his blood when word got out. Dean would never see him the same way again. Was it really worth it? Unleashing his inner demon just so he could kill Lilith? Sam didn't know.

"Sam, are you ready?" Ruby called from the doorway. Ruby had persuaded him to give in; she said he'd never be able to kill her unless he stopped fighting against what he was meant to be…who he was meant to be. She had hassled and hassled him until he'd started to believe that maybe she was right. He had to stop Lilith, stop her from hurting innocent people…punish her for killing Dean and making him endure all those months in hell. He had no choice; he just had to be the one to end her. Was he ready? He didn't know. A part of him was still unsure about this; what if he couldn't control himself anymore…what if he hurt Dean. Dean…Dean didn't even know what was going on. Sam had faked a huge argument with him and taken off with Ruby so that they could plan this. He hadn't liked the idea at first but later on as he tried to reason with himself he realised that he wasn't doing this to hurt Dean, he was doing it _for _Dean. He turned to face Ruby with an indifferent look on his face.

"I'm ready" he said as he walked towards her. But as he watched her smile, something snapped inside him and he felt hot, white pain running through his head. This was followed by a surge of anger. He needed to let it out somehow; he needed to kill someone, anything, and Ruby was there. Her eyes widened as she realised what was happening,

"N-No…Sam you can't send me back down there….it's Lilith you want to kill not me! You can fight it Sam…I know you can" she said in pleading tone. But her cries fell on deaf ears. Sam raised his hand and proceeded to pull Ruby out. She gasped as the first cloud of black smoke erupted from her mouth. Sam to his credit was trying hard to stop himself but he couldn't…he needed to do this. As the last of the black smoke disappeared back into Ruby as she fell to he ground he decided that he wasn't going to let her go that easily. He was going to make it hurt; make her wish that she'd never had anything to do with Sam, ever. Sam stood there as there was an eerie silence in the room. He felt very calm, a complete contrast as to how he'd felt before and slowly he realised that he'd gone 'dark side' and it felt good. _Really _good.


	2. Time is Running Out

A big thanks to _Erytha _for beta-ing this for me :D

* * *

**A week earlier**

Sam walked down the street quickly, his hands were shoved deep into his pockets and he was lost in thought completely. He was just about to enter the Meadow Motel where he and Dean had been staying when he saw a car with its engine running across the street from the entrance. Ruby. He was surprised that she'd waited for him right outside and so he figured that she must have something important to tell him. With a weary sigh, he crossed the street.

"What is it?" he asked simply. Ruby remained quite for a few seconds before saying

"Get in". Sam rolled his eyes but he still obliged, as soon as he closed the door Ruby spoke up, "There a five seals left Sam, five...you have to do something now Sam, because we're running out of time and I really think that you're ready now" Sam stared at her in shock. Five seals left? It seemed like yesterday when Ruby had appeared to tell him that there were just over half of 66 seals to be broken. Winning had still been within his reach, but now...he wasn't so sure. Lilith was closing in on them. She was winning.

"I don't believe it, "He murmured in disbelief. Ruby raised an eyebrow,

"Well you better believe it, the fate of the world is in your hands Sam, the angels have lost, and they can't win this anymore. But you can," Ruby paused and she turned to look at Sam, "If you don't do it then all that blood that's shed? It will be on your hands" Sam felt anger flaring up inside him. Why did it have to be this way? What if he couldn't win, kill Lilith...save Dean, hell save anyone. How the hell would he be able to live with that? Sam got out of the car without saying a word and he crossed the street and entered the motel. Ruby remained still for a few seconds with a strange expression on her face.

As soon as Sam saw Dean he knew that Dean knew about the seals as well. He guessed that the angels had told him. Sam wasn't interested in helping the angels. To them he was just a stain on their precious human race. There were no shades of grey with the angels. To them things were black or white; you were either a winner or a sinner and Sam guessed that somehow he was the latter. Some of the angels wanted him dead even though he'd been saving people for the best part of his life. But none of that mattered, not while he had demon blood inside of him. Sometimes Sam had the urge to give into his psychic powers; after all if he was going to hell he might as well enjoy the ride. But each time he thought that he came up with a reason to stay the way he was. What if he could save everyone? Then all of this would be worth it and Dean would be okay and that was all that mattered to him.

"So five seals to go..." Dean said finally in that tone he always used when he was trying to make out that wasn't scared. Sam, like always, could see right through it. The look of defeat in Dean's eyes was visible; he didn't think that they'd make it. Sam knew then that Ruby was right, he had to take Lilith out and he had to do it now. Sam sat down across from where Dean had been sitting,

"Don't worry, Dean, we'll stop her before it's too late". Dean's face remained indifferent and Sam figured that Dean was just worried. After a few minutes of silence, the uneasy atmosphere got the better of Sam and he mumbled something about needing some air and he left their motel room. Little did he know that of he'd come back into the room for just a few seconds he would have seen something that changed everything.

As Sam walked down the street he scanned it quickly for anything out of the ordinary but all he saw was a couple of cars and few people stumbling out of the bar across the street. He shoved his hands into his pocket as the cold air blew around him. There was a sudden gust of wind and Sam's hair blew into his eyes. As he was brushing his hair out of his face, Castiel appeared beside him with a grim look on his face. Sam stopped and his eyes widened and a look of surprised appeared on his face. He shook his head slightly in confusion, since when did angels appear to him?

"What do you want" Sam asked quietly, unable to keep the resentful tone from being heard in his voice. Castiel tilted his head to one side as he stared at Sam with a slight frown on his face. No matter how hard he tried he just couldn't understand Sam's plight, he just couldn't. This was one of the reasons why he'd agreed to do this, he had his doubts about everything but he was sure of this mission. It had to be completed. He knew that he should probably feel something, but in the end he just wondered if what they were doing was wrong. Did it go against what their God had taught them? But he still didn't feel anything for Sam, Sam had evil inside of him, he was pivotal to this war. And most importantly he could stop it.

"I take it that you've heard about the seals" Castiel said in a bland, emotionless voice.

"I heard" Sam shot back, his own voice also lacking emotion. Castiel sensed that Sam didn't know what he was about to ask. He didn't know about any of it; Dean hadn't told him. This meant that Sam didn't need to know, not until the very end.

"We need your help Sam, we need you to stop her" Castiel explained, his blue eyes staring straight into Sam's hazel ones. There was a long silence as the two of them glared at each other.

"Why?" Sam whispered finally, "Why do you need my help?"

"We need you to use your powers to kill Lilith" Castiel replied simply. Sam laughed dryly, he couldn't believe this.

"You're not serious..." he said with a bemused expression on his face. And he turned and walked off, leaving Castiel to stare at his retreating figure. He gasped as seconds later he nearly collided with Castiel who had appeared in front of him. Sam just didn't understand this. One minute the angels wanted him dead, they wanted all trace of the demon blood inside of him eradicated and the next they wanted his help? Something wasn't right here, Sam could feel it.

"Leave. Me. Alone" Sam said coldly, "Go and find someone else to do your dirty work for you" Castiel didn't even blink, he merely inched closer to Sam and he said,

"We won't force you Sam, but you're the only one who can stop her. We've lost….Earth's destiny is in your hands" And then he was gone. Sam was left standing in the street as the shadows of the night engulfed the light around him. He sighed and he walked back in the direction of the motel with his head bowed down.

***

Dean looked up from the TV as Sam entered the room, a look of concern on his face,

"Sam, where did you go" he asked. Sam ran a hand through his hair and sighed deeply,

"Nowhere" he muttered. Dean frowned and nodded to himself slightly. Like Sam would have told him anyway. It was like he didn't even know who Sam was anymore…they'd drifted further and further apart and now they just did their own thing. It was easier that way. For Sam anyways. Sometimes Dean wished that he rewind the last four years back to when Sam was still a goofy, little college kid. He would have given anything to get back the Sam who used to dote on him, listen to him….look up to him. But that's what growing up did to people, it made them become less dependent on people and Dean assumed that that was what had happened to Sam. Sam walked across the room and he sank down onto his bed and put his head in his hand. Dean turned the TV off as he looked at Sam and suddenly he was overcome with guilt. He had to tell Sam, he had to. But Sam got there first,

"Castiel came to me….he said…I..." Sam paused as he tried to think of the best way to say it, "he said that the angels needed my help, Dean" Dean looked away, his green eyes full of fear,

"Yeah, he told me…" Dean said in a quiet voice. Tensions had been running high between the brothers ever since they had been put under that Siren's spell. Neither of them had come out and said anything but the unease was there.

"And what, you didn't think you should tell me" Sam exploded and he glared at Dean angrily. Dean glared right back at him and said,

"Oh right and you tell me _everything _that Ruby says to you" Sam closed his eyes for a second as he sighed. He was sick and tired of them arguing about Ruby, they'd been over this so many times now and it always ended up the same way. Before he could say anything Dean said,

"I was scared Sammy, real scared, that's why I didn't tell you…" he looked away quickly, not wanting Sam to see the fear in the eyes. Fear of what was going to happen. Fear caused by Dean's failure to believe that he could save his brother. Sam couldn't stand this. He couldn't bear to see Dean getting so worked up about this when maybe he could save everybody. He could be a hero; he could repay back everything that Dean had ever done for him by putting an end to all of this.

"What are you scared of? What if I do this and everything goes away, no more angels on our backs, no more Ruby…" Sam said in a hopeful tone. Dean looked at his brother for a few seconds with a distressed look on his face. He knew then that if he didn't tell Sam now and Sam found out that he might lose his brother forever; in more ways that one. But he couldn't do it, not when he could still change things. He felt numb inside when he saw the way that Sam was looking at him. Dean knew that look too well, he'd seen it when they were kids, whenever Sam needed to be reassured. He wanted Dean to tell him that everything would be okay. But Dean couldn't do that, not when he knew that they weren't. Either Sam did this, or everybody died. Every thing was falling apart and Dean felt as though this was on rollercoaster they would never be able to get off. Sam must have picked up on something and realised that something wasn't right because he said,

"Dean what is it? What else did Castiel say?" Dean didn't answer straightaway. Nor did he tell Sam the truth, instead he said,

"You don't have to do this…please….there has to be another way…why risk this? I mean we either lose or win right?"

"Yeah, there _was _another way, Dean, but the angels are losing. They've asked for my help….what am I supposed to say…" Sam paused as he tried to choose his words carefully, "I would give anything not to have to do this, but I have to Dean, I'm the only one who can stop her, and I just can't let Lilith get away with this…I just can't…not after…" Sam broke off abruptly. He'd never really told Dean how much those 4 months had damaged him. Dean didn't know about all the hate and anger that he kept bottled inside. But once Lilith was dead all of that would go away, he would feel like himself again. He was sure of that…

"Not after what?" Dean asked.

"Not after what she did to you…." Was all Sam said, it was all he could say. He believed that his actions would say more than his words ever could. Dean realised that in one way or another Sam was doing this for him. He was trying to get payback. He was trying to make up for not being the one to save Dean from the pits of hell. Dean wanted to tell Sam that none of it had been his fault, and that he didn't blame him for anything of it, But before he could Sam's cell rang and Dean knew that it was Ruby. And that moment something occurred him, she was the cause of all of this and he didn't care how irrational it sounded; it was clear to him that there was only one solution. She had to die...


End file.
